1. Field of the Invention
The present invention relates to a lock device which is
locked and released through insertion of a lock card with plural holes punched therein;
2. Description of the Related Art
An example of such lock devices is disclosed in Japanese Patent Laying-Open Gazette No. 62-228578, which includes a slider having plural tumblers; a lock card with plural holes punched therein to determine the amounts of projections of the tumblers; a guide groove for guiding the lock card to the tips of the tumblers; and a mechanism for moving the slider only when the amount of projection of each tumbler becomes equal to a predetermined amount for completion of locking or releasing operation.
Another example disclosed in Japanese Patent Laying-Open Gazette No. 62-268481 further includes a step member formed in the slider to stop the lock card and move the slider upon the sliding pressure of the lock card.
In these prior art lock devices, the lock card moves the slider in a predetermined direction against the great resistance. Especially, in the latter structure, the step member formed in the slider temporarily stops the sliding of the lock card and prevents the smooth movement of the slider. These structures also require a number of parts for a sliding mechanism including tumblers and a slider, and a locking mechanism including engagement members and springs and are thereby not economically manufactured. In the above mechanism that the amounts of projections of the tumblers are determined by the holes punched in the lock card, forcible or too-quick sliding of a wrong lock card without the corresponding pattern of holes may cause mis-operation, that is, undesirable or accidental locking or releasing.